Comprehensive utilization method and application of lead-zinc tailings

Abstract

The invention discloses a comprehensive utilization method and application of lead-zinc tailings. The comprehensive utilization method comprises the steps that the lead-zinc tailings generated after lead-zinc separation of a separation plant enter a cyclone through a slurry pump to be screened and divided; and subsequently drying through a dryer. The tailings obtained after the lead-zinc tailings are treated are used for preparing cement-based self-leveling mortar for the ground and a cement-based ceramic tile adhesive, and the tailings, the cement-based self-leveling mortar for the ground and the cement-based ceramic tile adhesive all meet product quality detection. Potential threats of storage of the lead-zinc tailings to land resources and underground water are eliminated, the recycling rate and economic benefits of the lead-zinc tailings can be increased, and therefore the purposes of harmless, reduction and resourceful treatment of the lead-zinc tailings are achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of lead-zinc tailings treatment, and particularly relates to a comprehensive utilization method and application of lead-zinc tailings. Background Art

[0002] With the large-scale exploitation of mineral resources, a large number of solid wastes such as metallurgical slag, tailings, and waste rock are inevitably generated. Most of them do not pay enough attention to the treatment and disposal of tailings and non-ferrous metallurgical slag, and they are still in the state of low-level simple stacking, bringing great potential hazards to the environmental safety of soil and groundwater. The typical tailings and smelting slag represented by lead-zinc and the like have a huge stacking quantity and a high potential environmental risk. These typical tailings and smelting slag are mainly industrial wastes after the separation and purification of lead-zinc ores, with relatively high harmful components such as sulfur and alkali, and due to the low content of recyclable components in these residues, the economic benefits of treatment and disposal are low.

[0003] For example, when using bulk wastes such as mine tailings, construction waste, industrial waste, municipal sludge, and river-lake (canal) sea sludge to harmlessly produce and prepare building materials such as sand and gravel aggregates, high-strength ceramsite for structural concrete, functional ceramsite, and wall materials, it is necessary to pre-treat the lead-zinc tailings to remove the unusable parts. For example, the heavy metal content in the lead-zinc tailings is relatively high and the activity is low, so a large amount of tailings cannot be directly used in building materials. Therefore, it is particularly important to convert the lead-zinc tailings into available building materials. Summary of the Invention

[0004] The purpose of the present invention is to provide a comprehensive utilization method and application of lead-zinc tailings to solve the technical problem that the unusable parts in the existing lead-zinc tailings need to be removed.

[0005] To achieve the above purpose, the present invention provides the following technical solutions: A treatment method of lead-zinc tailings provided by the present invention includes the following steps: S1. The lead-zinc tailings generated after the separation of lead-zinc in the concentrator are fed into a hydrocyclone by a slurry pump for screening and shunting. The lead-zinc tailings slurry concentrated at the bottom of the hydrocyclone enters a dewatering screen for dewatering, and the dewatered tailings are transported to a transfer stockpile warehouse; the tailings liquid overflowing from the overflow port of the hydrocyclone and the tailings liquid dewatered by the dewatering screen enter a plate and frame filter press system, and the tailings generated after pressure filtration enter a drying system; S2. The tailings with a moisture content of 10% in the transfer stockpile warehouse are transported to the wet material bin of the drying system, and then transported to the feed bin of the dryer to be fed into the dryer for drying; S3. After drying, the moisture content of the tailings drops to 1%, and they enter the distribution bin at the discharge end for cooling, and enter a closed vibrating screen from the discharge port at the bottom of the distribution bin; S4. After being screened and classified by the vibrating screen, they are directly transported to a dry storage bin for temporary storage through a hoist, and then packaged later.

[0006] Further, the wastewater generated by the dewatering screen and the plate-and-frame filter press system in S1 is collected in a wastewater recovery pool, and a composite flocculant is added to the wastewater recovery pool. The weight percentage composition of the composite flocculant is 40 - 50% PAM + 30 - 50% PAC + 10 - 20% sodium humate. After flocculation, the supernatant is pumped to the high-level water pool of the concentrator and replenished into the ore dressing production process of the concentrator.

[0007] Further, the use of the composite flocculant can better optimize the wastewater treatment efficiency and recover valuable metal ions.

[0008] Further, the pond slag generated in the wastewater recovery pool is pumped out by a slurry pump, filtered and pressed, and then sent to a wet stock bin for recycling in the drying system.

[0009] Further, when using a dryer for drying in S2, CO2 gas is introduced into the drying gas, and mineral carbonation is carried out using the Ca / Mg components in the tailings.

[0010] Further, the dryer is equipped with a biomass hot blast stove, using biomass as raw material. The biomass burns in the hot blast stove, and a blower supporting the dryer provides combustion air. The temperature of the hot flue gas after biomass combustion is 400 - 500 °C, and heat exchange is carried out with the materials in the dryer.

[0011] Further, when the drying gas provided by the biomass hot blast stove enters the dryer, 20 - 30% CO2 gas is introduced, and mineral carbonation is carried out using the Ca / Mg components in the tailings to improve the mechanical properties of the tailings as aggregates.

[0012] Further, the flue gas outlet of the dryer is connected with a dust collector through a pipeline. The tailings dust collected by the dust collector is transported to the wet stock bin through a spiral conveyor pipeline for recycling in the drying system.

[0013] Further, before entering the vibrating screen in S3, the tailings can also be activated and solidified. The activation treatment is to add a composite activator accounting for 5% - 10% of the weight of the tailings to the tailings, and the solidification treatment is to add a heavy metal stabilizer accounting for 0.5% - 2% of the weight of the tailings to the tailings to solidify the residual heavy metals in the tailings.

[0014] Further, the weight percentage composition of the composite activator is 50 - 70% NaOH + 30 - 50% Na2SiO3. The heavy metal stabilizer is a composition of one or more of phosphates, sulfides, gypsum, organic polyphosphonic acids and cement, and the ratio of one or more of phosphates, sulfides, gypsum, organic polyphosphonic acids and cement is 1:8 - 10.

[0015] Phosphates, sulfides, and gypsum have good solidification or stabilization effects on lead and zinc. Organic polyphosphonic acids can precipitate almost all monovalent and divalent metals, such as copper, cadmium, mercury, silver, lead, and tin. And when heavy metal ions exist in the form of complex salts and cannot be completely removed by the hydroxide precipitation method, organic polyphosphonic acids can still play a good removal role; organic polyphosphonic acids are harmless to the environment, and the metal precipitates are very stable and will not release heavy metals even at high temperatures of 200 - 250 °C; adding a small amount of cement can further improve the solidification effect of phosphates, sulfides, gypsum, and organic polyphosphonic acids on heavy metals.

[0016] Furthermore, the addition of a composite activator can improve the gelling activity of tailings by 50 - 70%. 50 - 70% NaOH + 30 - 50% Na2SiO3 can promote the reaction of active components (such as Al2O3 and SiO2) in the tailings with Ca(OH)2 to form C-S-H and C-A-H gels, and these gels have high gelling properties, making the tailings more suitable as building material raw materials; the solidification treatment ensures the environmental protection and safety of building materials products, and the leaching concentration meets the GB 5085.3 - 2007 standard.

[0017] The present invention also provides the application of tailings obtained by a comprehensive utilization method of lead-zinc tailings in the preparation of floor cement-based self-leveling mortar and cement-based ceramic tile adhesives, and the tailings, floor cement-based self-leveling mortar, and cement-based ceramic tile adhesives all meet the product quality inspection.

[0018] Furthermore, the proportion of tailings in the cement-based self-leveling mortar is 30% - 50%, and the tailings are surface-treated with 1% - 3% silane coupling agent. By chemically modifying the tailings, the interfacial bonding strength is improved, thereby increasing the proportion in the cement-based self-leveling mortar.

[0019] Furthermore, the tailings in the cement-based self-leveling mortar can be ground into fine particles before being added, and the tailings are made to reach sufficient fineness through grinding. The surface area of the fine particles increases, increasing the contact area of the reaction, thereby improving the reaction rate and strength; thus, the strength of the cement-based self-leveling mortar prepared from the tailings is improved.

[0020] Based on the above technical solutions, the embodiments of the present invention can at least produce the following technical effects: A comprehensive utilization method and application of lead-zinc tailings provided by the present invention, the obtained tailings, floor cement-based self-leveling mortar, and cement-based ceramic tile adhesives all meet the product quality inspection. By treating the lead-zinc tailings, the present invention eliminates the potential threats of the storage of lead-zinc tailings to land resources and groundwater, and can also improve the recovery rate and economic benefits of lead-zinc tailings, thereby achieving the purpose of harmless, reduction, and resource treatment and disposal of lead-zinc tailings.

[0021] Activating and solidifying tailings can improve their cementitious activity, making them more suitable as building material raw materials. The solidification treatment ensures the environmental protection and safety of building materials products. Subsequently, chemical modification of the tailings is carried out to enhance the interfacial bonding strength, thereby increasing their proportion in cement-based self-leveling mortar. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] To more clearly illustrate the technical solutions in the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on the structures shown in these drawings.

[0023] Figure 1 It is a schematic flowchart of an embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0024] The following will combine the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the protection scope of the present invention.

[0025] Embodiment 1 As Figure 1 shown, the present invention provides a method for treating lead-zinc tailings, including the following steps: S1. The lead-zinc tailings generated after the separation of lead and zinc in the concentrator are fed into a hydrocyclone by a slurry pump for screening and splitting. The lead-zinc tailings slurry concentrated at the bottom of the hydrocyclone enters a dewatering screen for dewatering, and the dewatered tailings are transported to a transfer stockpile warehouse. The tailings liquid overflowing from the overflow port of the hydrocyclone and the tailings liquid dewatered by the dewatering screen enter a plate and frame filter press system, and the tailings generated after pressure filtration enter a drying system. S2. The tailings with a moisture content of 10% in the transfer stockpile warehouse are transported to the wet material bin of the drying system, and then transported to the feed bin of the dryer to be fed into the dryer for drying. S3. The moisture content of the dried tailings drops to 1%, and they enter the distribution bin at the discharge end for cooling, and enter a closed vibrating screen through the discharge port at the bottom of the distribution bin. S4. After being screened and classified by the vibrating screen, they are directly transported to a dry storage bin for temporary storage through a hoist, and then packaged.

[0026] In this embodiment, the wastewater generated by the dewatering screen and the plate-and-frame filter press system in S1 is collected in the wastewater recovery tank. Polyacrylamide and polyaluminum chloride flocculants are added to the wastewater recovery tank. After flocculation, the supernatant is pumped to the high-level water tank of the concentrator and replenished into the ore dressing production process of the concentrator.

[0027] In this embodiment, the pond slag generated in the wastewater recovery tank is pumped out by a slurry pump, filtered and pressed, and then sent to the wet material bin for recycling in the drying system.

[0028] In this embodiment, the dryer in S2 is equipped with a biomass hot blast stove. When drying in S2, 30% CO2 gas is introduced, and mineral carbonization is carried out using the Ca / Mg components in the tailings to improve the mechanical properties of the tailings as aggregates.

[0029] In this embodiment, the flue gas outlet of the dryer is connected to a dust collector through a pipeline. The tailings dust collected by the dust collector is transported to the wet material bin through a spiral conveyor pipeline for recycling in the drying system.

[0030] In this embodiment, before entering the vibrating screen in S3, the tailings can also be activated and solidified. The activation treatment is to add a composite activator accounting for 10% of the weight of the tailings to the tailings, and the solidification treatment is to add a heavy metal stabilizer accounting for 2% of the weight of the tailings to the tailings to solidify the residual heavy metals in the tailings.

[0031] In this embodiment, the weight percentage composition of the composite flocculant is 50% PAM + 30% PAC + 20% sodium humate; the composite activator is 70% NaOH + 30% Na2SiO3, and the heavy metal stabilizer is a composition of gypsum and cement, with gypsum:cement = 1:10.

[0032] Example 2 Different from Example 1, the weight percentage composition of the composite flocculant is 50% PAM + 30% PAC + 20% sodium humate; the composite activator is 50% NaOH + 50% Na2SiO3, and the heavy metal stabilizer is a composition of organic polyphosphonic acid and cement, with organic polyphosphonic acid:cement = 1:10.

[0033] Example 3 Different from Example 1, the weight percentage composition of the composite flocculant is 50% PAM + 30% PAC + 20% sodium humate; the composite activator is 60% NaOH + 40% Na2SiO3, and the heavy metal stabilizer is a composition of sulfide and cement, with organic polyphosphonic acid:cement = 1:10.

[0034] Comparative Example 1 Different from Example 1, the weight percentage composition of the composite flocculant is 50% PAM + 30% PAC + 20% sodium humate; the composite activator is 50% NaOH + 50% Na2SiO3, and the heavy metal stabilizer is gypsum.

[0035] Comparative Example 2 Different from Example 2, the weight percentage composition of the composite flocculant is 50% PAM + 30% PAC + 20% sodium humate; the composite activator is 50% NaOH + 50% Na2SiO3, and the heavy metal stabilizer is organic polyphosphonic acid.

[0036] Comparative Example 3 Untreated tailings The heavy metal contents of the tailings obtained in the above Examples 1-3 and Comparative Examples 1-2 were detected, and the results are shown in Table 1: Table 1 The tailings of the above Examples 1-3 were used to prepare cement-based self-leveling mortar for ground and cement-based ceramic tile adhesive. The proportion of tailings in the cement-based self-leveling mortar was 30%-50%, and the tailings were surface-treated with 1%-3% silane coupling agent. The finally obtained cement-based self-leveling mortar for ground and cement-based ceramic tile adhesive were subjected to quality inspection and heavy metal detection, and the results are shown in Tables 2, 3, 4, and 5: Table 2 Quality Inspection of Cement-Based Self-Leveling Mortar for Ground Conclusion: Judging according to the standard of "Cement-Based Self-Leveling Mortar for Ground" JC / T 985-2017, the inspected items of this sample are qualified. The tailings of Examples 1-3 can be used for the preparation of cement-based self-leveling mortar for ground.

[0037] Table 3 Heavy Metal Content Detection of Cement-Based Self-Leveling Mortar Detection Index Detection Result (mg / l) Limit Value (mg / l) Arsenic 0.04 0.1 Lead 0.01 0.3 Cadmium 0.005 0.03 Chromium 0.16 0.2 Copper 0.10 1.0 Zinc 0.61 1.0 Conclusion: The heavy metal content of the cement-based self-leveling mortar for ground prepared from the tailings of Examples 1-3 is far lower than the threshold specified by the standard.

[0038] Table 4 Quality Inspection of Tile Adhesive Test Items Standard Requirements (Type C1S1) Measured Value Individual Judgment Tensile Bond Strength / MPa ≥0.5 0.6 Qualified Tensile Bond Strength after Immersion in Water / MPa ≥0.5 0.6 Qualified Tensile Bond Strength after Thermal Aging / MPa ≥0.5 0.5 Qualified Tensile Bond Strength after Freeze-Thaw Cycles / MPa ≥0.5 0.5 Qualified Tensile Bond Strength with Drying Time ≥ 10 min / MPa ≥0.5 0.6 Qualified Tensile Bond Strength with Drying Time ≥ 20 min / MPa ≥0.5 0.6 Qualified Tensile Bond Strength with Extended Drying Time ≥ 30 min / MPa ≥0.5 0.6 Qualified Tensile Bond Strength at 6 h / MPa ≥0.5 0.5 Qualified Slip / mm ≤0.5 0 Qualified Lateral Deformation / mm ≥2.5，≤5 2.7 Qualified Conclusion: Judging according to the standard of "Ceramic Tile Adhesive" JC / T 547-2017, the inspected items of this sample are qualified. The tailings of Examples 1-3 can be used for the preparation of cement-based ceramic tile adhesive.

[0039] Table 5 Heavy Metal Content Detection of Tile Adhesive Detection Index Detection Result (mg / l) Limit Value (mg / l) Arsenic 0.04 0.1 Lead 0.01 0.3 Cadmium 0.005 0.03 Chromium 0.11 0.2 Copper 0.11 1.0 Zinc 0.76 1.0 Conclusion: The heavy metal content of the tile adhesives prepared from the tailings in Examples 1-3 is far lower than the threshold specified by the standard.

[0040] The structures, functions, and connection forms disclosed herein can be implemented in other ways. For example, the embodiments described above are merely illustrative. For instance, multiple components can be combined or integrated into another component. Additionally, in each embodiment herein, the functional components can be integrated into one functional component, or each functional component can exist physically alone, or two or more functional components can be integrated into one functional component.

[0041] The above are only the preferred embodiments of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the inventive concept of the present invention, several modifications and improvements can still be made, and these all fall within the protection scope of the present invention.

Claims

1. A comprehensive utilization method for lead-zinc tailings, characterized in that, It includes the following steps: S1. The lead-zinc tailings generated after the beneficiation of the ore dressing plant are fed into a hydrocyclone by a slurry pump for screening and shunting. The lead-zinc tailings slurry concentrated at the bottom of the hydrocyclone enters a dewatering screen for dewatering, and the dewatered tailings are transported to a transfer stockpiling warehouse; The tailings liquid overflowing from the overflow port of the hydrocyclone and the tailings liquid dewatered by the dewatering screen enter a plate and frame filter press system. The tailings generated after pressure filtration enter a drying system; S2. The tailings with a moisture content of 10% in the transfer stockpiling warehouse are transported to the wet material bin of the drying system, and then conveyed to the feed bin of the dryer and fed into the dryer for drying; S3. After drying, the moisture content of the tailings drops to 1%, and they enter the distribution bin at the discharge end for cooling, and enter a closed vibrating screen from the discharge opening at the bottom of the distribution bin; S4. After being screened and classified by the vibrating screen, they are directly transported to a dry storage bin for temporary storage by a hoist, and then packaged later.

2. The comprehensive utilization method of lead-zinc tailings according to claim 1, wherein In S1, the wastewater generated by the dewatering screen and the plate and frame filter press system is collected in a wastewater recovery pool. A composite flocculant is added to the wastewater recovery pool. The weight percentage composition of the composite flocculant is 40-50% PAM + 30-50% PAC + 10-20% sodium humate. After flocculation, the supernatant is pumped to the high-level water pool of the ore dressing plant and supplemented to the ore dressing production process of the ore dressing plant.

3. The comprehensive utilization method of lead-zinc tailings according to claim 2, wherein, The pond slag generated in the wastewater recovery pool is pumped out by a slurry pump, pressure filtered and then sent to the wet material bin and enters the drying system for recycling.

4. The comprehensive utilization method of lead-zinc tailings according to claim 1, wherein, When drying is carried out by the dryer in S2, CO2 gas is introduced into the drying gas, and mineral carbonization is carried out using the Ca / Mg components in the tailings.

5. The comprehensive utilization method of lead-zinc tailings according to claim 1, characterized in that, The flue gas outlet of the dryer is connected with a dust collector through a pipeline. The tailings dust collected by the dust collector is transported to the wet material bin by a screw conveyor pipeline and enters the drying system for recycling.

6. The comprehensive utilization method of lead-zinc tailings according to claim 1, wherein Before entering the vibrating screen in S3, the tailings can also be activated and solidified. The activation treatment is to add a composite activator accounting for 5%-10% of the weight of the tailings to the tailings. The solidification treatment is to add a heavy metal stabilizer accounting for 0.5%-2% of the weight of the tailings to the tailings to solidify the heavy metals remaining in the tailings.

7. The comprehensive utilization method of lead-zinc tailings according to claim 6, characterized in that, The weight percentage composition of the composite activator is 50-70% NaOH + 30-50% Na2SiO3. The heavy metal stabilizer is a composition of one or more of phosphates, sulfides, gypsum, organic polyphosphonic acids and cement.

8. Use of the tail sand obtained by the comprehensive utilization method of lead-zinc tailings according to any one of claims 1-7 in the preparation of cement-based self-leveling mortar for the ground and cement-based ceramic tile adhesives, characterized in that, The tailings, the cement-based self-leveling mortar for the ground and the cement-based ceramic tile adhesive all meet the product quality inspection.

9. Use of the tailings prepared by the comprehensive utilization method of lead-zinc tailings according to claim 8 in the preparation of cement-based self-leveling mortar for the ground and cement-based ceramic tile adhesives, characterized in that, In the cement-based self-leveling mortar, the tailings account for 30%-50%, and the tailings are surface-treated with 1%-3% silane coupling agent.

Images